Pipe protector



Sep@ E953 a E. PFLAUMER 2650,619

` PIPE -PROTECTOR Filed July 15, 1949 Patented Sept. 1, 1953 AUNTEDSTATES PIPE PROTECTOR Robert E. Paumer, Winnetka, Ill., assignor toAmerican-Marietta Company, a corporation of Illinois Application `luly13, 1949, Serial No. 104,460 4 Claims. (Cl. 13S-64) This inventionrelates to an armor sheet and to the use of that sheet in protecting oiland gas pipes, particularly pipes laid in rocky terrain.

As is known, oil and gas are now commonly transported from place toplace as by pumping the same through pipes of circular section havingdiameters usually varying from about inches to 36 inches. rlhese pipesare protected from water and other corrosive forces prior to burial inthe ground by covering the pipes With a thin, exible Waterproof materialor membrane. The membrane usually used consists of a flexible sheet ormatrix of burlap, cloth Woven from glass bers (sold under the trade-markFiberglas) and like materials capable of being impregnated with thesaturant, pitch, asphalt, coal tar residues and like Water-imperviousmaterials, used to saturate, coat and bond the matrix to the pipe. Themembrane is usually applied to the pipe in the form of a tight wrapping,preferably a continuous Wrapping, and the covered pipe is then loweredinto a `ditch and covered with earth.

During the lowering of the covered pipe into the ditch and the coveringthereof with earth the membrane is exposed to conditions and forceswhich make breaks therein and thus provide exposed portions holidays ofpipe which are subject to corrosive attack, leading eventually to leaksand pipe failure. This is a serious problem in rocky country7 for notonly is the membrane subject to damage from Vthe slings and othersupporting members before and during the 10W- ering of the coated pipeinto position in the ditch,

-but to damage from falling rocks during the backiilling operation, fromrocks and coarse sub-soil which are present in bottom of the ditch andon Which the Weight of the pipe may be supported, and from rocks, smallstones and coarse sand Whose sharp projections may be forced against thepipe by the Weight of the backll material. The stress caused by volumechange of the subsoil immediately surrounding the pipe during periods ofchanging moisture content of this subsoil is a further and notinfrequent source of holidays in all terrains Where pipe is laid, rockyor otherwise.

In consequence of the large economic losses resulting from holidaysgreat care is exercised in supporting the wrapped pipe and in loweringthe same into the ditch. Additionally, in accordance With conventionalprior art practice, the

' Wrapped pipe isprotected by a dirt padding.

Thus the bottom of the ditch is covered with a layer oi padding ofgraded dirt or sand approximately four inches in thickness and themembrane-covered pipe is lowered onto this padding. A padding of similarmaterial and thickness is then applied to the top of the covered pipeand only then is the ditch backlled with the coarser material removedfrom the earth in making the ditch. It is manifest that this paddingprocedure is an expensive one, particularly in mountainous 2 areas wherelarge volumes of clean earth suitable for the padding must be brought tothe site.

Apart from the economic standpoint, this prior art method of protectingmembrane-covered pipes laid in a ditch is objectionable because it isnot possible to apply a padding of dirt of uniform composition andthickness about the pipe. In consequenca the covering about the pipe issubjected to varying forces throughout its length. with the result thatholidays sometimes occur from this source.

In accordance with the present invention I place about themembrane-covered pipe before it is lowered into the ditch, a shield orarmor of a material which not only protects the covered pipe from theslings but from falling rock and the other hazards heretoforeencountered in laying the covered pipe in the ditch. In consequence ofthis method of protecting the membrane-covered pipe the protection issubstantially uniform throughout the length of the pipe and the need forpadding about the pipe is eliminated. The advantage flowing from theelimination of padding is a great one, for with it there is eliminatedalso the need for dump trucks, loading devices and the large number oflaborers required for the application of the padding.

The armor material of the present invention is a rigid, self-sustainingsheet capable of Withstanding impact, such as that from falling rock,and highly resistant to moisture. A,At spaced intervals throughout onedimension of the armor sheet flexible joints or hinges are provided sothat the sheet may be made to conform generally to the circular contourof the membrane-covered pipe. In the .preferred form of the presentinvention the sheet is made to conform as closely as possible to thecontour of the membrane-covered pipe. One or more of such sheets may berequired to completely or substantially completely encircle themembrane-covered pipe and when the pipe is so encircled, the armor is inthe form of a polygon the sides of which have substantially only a linecontact or a limited region of contact with the covered pipe. Thesesides extend tangentially of the pipe and are joined at the hinges, thusforming the angles of the polygon. Beneath each of these angles andextending substantially throughout the distance between the lines ofcontact of an adjacent pair of sides is a space which provides room forthe relatively rigid over-lying armor to give under impact and thusreduce and in many instances actually eliminate the force of fallingrocks which, if not for the armor, would make breaks in the membranecoating. Most of the covered pipe is protected by such spaced overlyingstructures and hence there is very little of the membrane-coated pipewhich normally has direct contact With the armor and what little thereis is spaced. In consequence there is very little of the falling rockwhich will strike the armor at the spaced regions of its contact Withthe pipe and have the force of impact Tried erste@ the 11i iriay` ,bewrapped.

brane from the hazards of falling rock androm like hazards, as Well asfrom, 'thleioroestransy mitted to the membrane bytheslngpsed in loweringthe protected pipe into the ditch.

The invention will be readilynderstoodfrom the following detaileddescription of the illus# trative embodiments shown in the acornpjnyingdrawings, in which:

Figure -1 is aJr'agmenta-ry. side elevationof Y, a pipe .Whiohisarmored.A andprotected, in accord: ance with, vthe .present invention,portions of the pipenovering beingiprogressively broken away;

.'Fg. 2 isa perspectveview of one ofthe preferred-armor units or sheetsof the present, in-

vntion; .Fig 3.'S-ja1;transverse section taken along the line.33,ofEig.,l;.,. i Fieeisanenlargedvyew otarasment of 3, showing moreclearly the relationship of the armor tothe pipe; i

trg... isa; transverse. secties -Qi-.thefpire and a citahin-whichthenipeis @beleid and covert@- .with -'ba ekf 111i11usbrati,g a mathe@ that beemployedto enase 4the .pipe with the armor sheet offtheprlesen@-lYQOlly1 Eiglfis v ayiew similar `to Fig. 3 of a modied form of the iinyeZFLefIl ist-a new me fieri ferm Qi meenten.

preferred armer zal closely 1the .armor sheets conf new..

'abatata-,min

able meiribrane is'fcloth woven from' glass@ fibers iW'lnh is 01;; under@strademark fleiberglas.

lwldeiyf "ser from "'qllal parts by.' Weight t-O. from 'The compositionof the preferred armor sheet described above is as follows:

Per cent by weight The overall thickness of the mastic core and thefacing sheets may vary rather widely say, for example, from aboutone-eighth inch to threeeighths inch. A preferred thickness isthree-sixteenths of an inch.

The armor sheet is a rigid, self-sustaining, water-impermeable sheethaving a very substantial structural strength, comparable to a plasterwallboard, and having great resistance to impact. The sheet is flexibleand has some elasticity and hence when struck by a falling object, suchas a stone, it gives under the impact of the stone 'and tends to returntowards its original position. Under conditions of temperature at orabove the melting temperature of the asphalt materials used in makingthe armor sheet, it may be shaped or molded. Under conditions normallyencountered in storage, transportation and use, it maintains its rigid,self-sustaining form.

When the armor sheet is made up and cut to the desired size it is runthrough a set of grooving or creasing rollers which press against oneside of the sheet at spaced intervals, as at Il, to form the fold linesor so-called hinges or flexible joints hl which enable the sheet to bebent, preferably in one direction, but do not interfere with the normalhandling and shipping of the product as a iiat sheet. Other forms ofhinges or flexible joints may, of course, be used. The spacing betweenthe grooving or hinge-forming rollers may be varied, as desired, but itis preferred that they be spaced fairly close together, as indicated inthe drawings, so that the armor sheet may be made to conform as closelyas po..- sible to the contour of the pipe which it is to embrace, asshown in Fig. 3. The number of socalled hinges in a sheet depends, ofcourse, upon the size of the sheet and the size of the pipe to beembraced thereby.

As shown in Fig. 3, the pipe is encircled by two armor sheets thebutting edges of which, indicated by the numeral I8, are preferably onopposite extremities of the horizontal diameter of the pipe, so as to beout of the line of direct travel of any stones falling on the pipe as itis being lowered into the ditch, indicated by the numeral I9. The armorsheets encircling the pipe are in the form of a polygon the sides 20 ofwhich have only a very limited region of contact with themembrane-covered pipe. Each side 20 extends tangentially of the pipe andeach adjacent pair of sides on each armor sheet is joined at the creaseline Il which, in effect, constitutes an angle of the polygon. Beneatheach angle of the polygon is a space 2| within which the armor sheet maygive under impact and from which it tends to spring back towards itsoriginal position after impact. The portion of each side 20 extendingoutwardly from the region of contact of the side with themembrane-protected pipe acts like a spring. For best results, it ispreferred that these spring-like, projecting portions be ofsubstantially equalI length and that 6 there be more than four sides inthe polygonal armor about the membrane-covered pipe.

Tests were conducted on membrane-covered pipe protected with the armorsheet illustrated in Figs. 1 to 4. These tests consisted of droppingrocks of Various sizes from a height of ve feet directly on the armorabout the membranecovered pipe. In one test the rock was 11.5" x 9.5 x 3in size and it struck the armor with its flat surface. In another testthe rock size was 17 X 8" x 4 and it struck the armor with one of itssharp cutting edges. In still another test the rock size was 6" x l2 x2.5"

and it also struck the armor with a sharp cutting made but a slight markon the membrane. Further tests were made by means of an electronicdetector, in accordance with conventional procedures, to determine iftherewere holidays in the membrane and these tests indicated that therewere none even in those portions of the membrane immediately beneath theareas where the rocks struck the armor. The atmospheric temperature atthe times of each of the tests referred to above was F.

A preferred way of encircling the membraneprotected pipe with the armorsheet illustrated in Fig. 2 is as follows. A pair of such sheets aresuperposed on each other on top of the pipe, with the crease lines l1down, and these superposed sheets are bent along the crease lines toroughly conform with the pipe. At suitable intervals, usually four toiive feet in the case of 4 X 8 armor Sheetastrapping of ber or steel,such as strapping I3, is loosely put in place around the circumferenceof the assembly of the two armor sheets and the membrane-protected pipe.The top armor sheet is then turned in the strapping to cover the bottompart of the pipe. The strapping acts as a sling to hold the armor sheetsin place and when they are properly positioned the strapping can then betightened to the desired tension. As pointed out above, it is preferred.

that the edges of the sheet form butt joints on opposite diameters ofthe horizontal diameter of the pipe; however, the edges of the twosheets may overlap or they may be left slightly spaced apart, thusleaving small gaps on the circumference.

ditch l S.

filled With backfill.

In the modification shown in Fig. 6 the membrane-protected pipe is shownarmored with a.

single sheet 22 of the armor material described above. This sheet isshown as having ve creaselines or hinge portions 23, to facilitateencircle-I ment of the membrane-'protected pipe with thev armor sheet.These are double acting hinges,r

permitting bending of the sheet in either direc-- tion. The armor sheet,in section, is in the form. of a triangle each side of which has only alimitedv region of contact with the membrane-protected pipe. The ends ofthe armor sheet are in butting:

relationship, as indicated at 2li.`

The third rock also sub-` stantially penetrated through the armor and itsaisi flat, Bartime beine tangentiallydisposed having only a limitedcentral region thereof in contact W-itl'i-.the membrane-covered pipe,Where- 5.- by a spaceV is formedibetxveenthearmor andzthe pipeintheregions. betweenthe saidf limited., re'- cal` an@ ppm/ide@ Wit-Ag;A1-,11'i11gemgregge?v armor and thearrangementof;thasaidffiatporjhingszghgojgaclili 1Q tionsabout the membrane-covered pipe being w l ,lr I 11; mesenger u suchthat the encircling armor is in the form of aShowmth ends! 01? Sheets@ and2if0r41 bt i1. Relxgoe. jointhsfas at 'z'galp "uglkth may @ym-131B. o; 3;, In combination with acylindricalpipe-covbe spacedsnghnw am? asindicateaabqve; ered with; aWaterrimiermeabiemembraneto protect the pipe against;corrosiomanyarmorencirciing themembrane-covered pipe; saidVv encircling armorcomprising asel'fesustaining, water-impermeable sheet capable oi'flexing along preformedrjfoldflines and resistant to 1' ailingofparallel;nrigii, iatmportionsfalternating with parallel' folrcilinesypressed into said sheet from one side thereof'i-so;thatsaidsheetliay/be folded- ILh-yvdesg-ibeg arplefem-:edyembgiqt in onedirection onlyjs'a-idj sheet being folded mem@ my'flxmrlghtx'n gm'a'p @aof 25. aboutthe p ipewith theside thereof inwhich *thev thatfshtjtol b'ttdj* 'l `foldlineswere pressed'adjacent-tosaidepipe each S'd" ofthesaidjilatportiens bei-ngrtangentiallydisposed.With'respectto'themembrane-covered pipe such that theencircling; armor isin 'the'form of ya polygon beneath eachi angle Vofwhichl isi-a space imp-act.

if In combinationwith a cylindricalfpipecovered` witha Water-impermeablemembrane. to protect -the1pipegagainstecorrosion; anarmor venf-Acircling the-membrane-covered pipe, said encirciing armorV comprising aself-sustaining, water-impermeable-sheet capable of ilexingalong and thelike; sai-d sh'eet comprisingfa Water-impermeable mastic` oorehavingasphalt-impregnatedsheets -aiheredlto the opDQSite sides` thereof,Vsaisi` core comprising a' homogeneous mixture of fasphaltfinorganicefiller materialand '-broiismate1ial,andsaidsheetbeing divided`into va `pluthereof so that said, sheet may---befolded-in one directiononly?y saidsheet `being-folded about the pipe witht-he side'thereofeinwhichI the `fold linesv with .respect totheElrnernlz;ranez-.co'vere,ci pipaand having only 'alimii'idieniral;legion teoria contactwith the membranefcovere'clWhere-l.v bya space'is fomgd heifweenthearmpr and the.; pipe11i-"the:rgionsibeiween.the-fsa; li.,liiiflfii'eil Are.:- gionsof.contactgpfithefsaiiflatrig pqrtionsanda the pip'efthe allang-amminithelsaid. let-.perf .Y tions about the meibrane-cove d.;pipe.;loeiiiigg;Suchthaf? 1th@ enilmgxar-mmr f. -fthi Qrmfothe.armoiasheetmayzfgivelWunder: impact; ap01ygon. ROBERTE.PFI-yAIii/LER.Y

2. Incomblnation witlifa cylind11Jca1,. pipe cove... n ereawithlafwatelf" ,we eferemesliesiiri,the.ieofthls patentv UNITE@ .SATESEBATENTSfNumber Name f Date 55. said atportions beingtangentially'- disposedwith= ment ottii-e said atportions andltold lines aboutAmthemembrane-covered pipe being sucht that.' the encircling lari-norisin= the form of-fa :polygon be, neathleachangie of .'Whiohfis a spacewithinswhich with respect to the membraneyooveredjpipefand l gins ofcontact of.thesaidflat.rigidlportionsand thej the pipe,therebeing.morathaniour sides in they rocksh and the like,saidsheet-having aplurality` and( having only-a limitedcentral regionthereot *n inV Contact lwith theA membrane-covered'-pipe, thevar-rangementv of thesaicl=- iiat` portions Vanaf fold' lines, about themembrane-covered pipe being-` With'inwhich thearifnor` sheet may giverunderpreformedyf o1d linesfandiesistant to `fallingrocksra1ityofparallel, rigid,A flat portions v:by f parallelv 4p folcl linesfpressed.: into said-sheet'irom one: side- Werepressed#adjacentwtosaidpipefeaeh of thefrespecttothe-membrane-covered-pipe andfhaving only 51a dimitedIcex-itral reg-ion :thereofeinI contact. Wit-la' the membrane-covered-:pipef: thefarrangee '293,572 Krahenbeihl et al. Feb;- 19,31884.

f1 Xiliealgeefqm 1,io1:,9'9o.- Bird etaiA Juneau, 1914.

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iblejoint portions, ,eachzz'nfisaicij ointportions con-Q 2318.9,492.:vLamberti;

-...m Angeli); `1937 meeting a pair 0f Saidflatewriionsfceachfof@hee-wi;2:29..15413f1 JalinekalieMmwasepti29fl9e2-

